A conventional X-ray CT apparatus is configured to have an X-ray tube and an X-ray detector which are arranged opposite to each other on both sides of a subject P. Further, the X-ray detector is configured to have a plurality of channels of detecting elements arranged along a direction (channel direction) perpendicular to the longer side direction of a top plate, the longer side direction being the direction of the body axis of the subject.
Various types of X-ray detectors can be used for the X-ray CT apparatus. One of detectors being used for the X-ray CT apparatus in general is, for example, a scintillation detector. The scintillation detector includes a scintillator being a detecting element, and a photodiode being an optical sensor.
Further, an X-ray computed tomography apparatus (X-ray CT apparatus) using a photon counting type detector has been developed in recent years. The photon counting type detector is configured to individually count photons derived from X-rays transmitted through the subject. As for the photon counting type detector, there have been disclosed a technique counting photons derived from X-rays, for example, a semiconductor detector configured, by using a detecting element, to perform direct conversion of photons derived from X-rays incident on the detector, and a detector configured, by using a scintillator, a light guide, or a photomultiplier tube, to perform indirect conversion of the photons.
In the conventional techniques, a data collection apparatus using the photon counting type detector is configured such that a count value corresponding to the energy of an X-ray transmitted through the subject is acquired by individually counting photons derived from the X-rays transmitted through the subject. Further, the data collection apparatus is configured such that the energy region is divided into a plurality of regions, and such that the data based on the count values are collected for the respective divided energy regions.
However, in the case where the data collected by the data collection apparatus are transmitted and stored, and where the number of the divided energy regions is large, the amount of data is increased in proportion to the number of the divided energy regions.
For this reason, there is a problem that, in order to transfer (transmit) the collected data, it is necessary to secure a band for transferring the data and to increase the storage capacity of a storage apparatus.